vcdExtra (version 0.5-2)

Detergent: Detergent preference data

Description

Cross-classification of a sample of 1008 consumers according to (a) the softness of the laundry water used, (b) previous use of detergent Brand M, (c) the termperature of laundry water used and (d) expressed preference for Brand X or Brand M in a blind trial.

Usage

data(Detergent)

format

A 4-dimensional array resulting from cross-tabulating 4 variables for 1008 observations. The variable names and their levels are:

rll{ No Name Levels 1 Temperature "High", "Low" 2 M_User "Yes", "No" 3 Preference "Brand X", "Brand M" 4 Water_softness "Soft", "Medium", "Hard" }

source

Fienberg, S. E. (1980). The Analysis of Cross-Classified Categorical Data Cambridge, MA: MIT Press, p. 71.

References

Ries, P. N. & Smith, H. (1963). The use of chi-square for preference testing in multidimensional problems. Chemical Engineering Progress, 59, 39-43.

Examples

data(Detergent)

# example goes here
mosaic(Detergent, shade=TRUE)

(det.mod0 <- loglm(~ Preference + Temperature + M_User + Water_softness, data=Detergent))
# examine addition of two-way terms
add1(det.mod0, ~ .^2, test="Chisq")

# model for Preference as a response
(det.mod1 <- loglm(~ Preference + (Temperature * M_User * Water_softness), data=Detergent))
mosaic(det.mod0)